I volunteer (I am the tech guy) at a charter school for exceptional children. After a recent minor safety issue came up between a student and a staff member at the school, we have been searching for a better communications solution to help stay in contact. Originally, we were relying on cellphones for emergency communications – not going to cut it long term. I have looked at Wifi solutions and Cell Phone apps but they lack the “instant” communications required for an emergency situation.

As we try to figure out the best solution, I have kind of wandered into a political briar patch between the school admins, a parent who also a significant donor to the school, a Motorola dealer in our county, and the school administration.

An EF Johnson dealer in another county is related to one of the school’s parents/major donors. I could use some straight answers about EF Johnson 5100 series radios from people who know the equipment and modern RF systems in general. Any other helpful commentary, links, guidance, is also welcome. I am a software developer by trade, had my HAM license as a kid, but in the deep end of the pool on these issues to be honest. As the school tech guy, school leadership is asking me to be the “neutral party” on this issue and find a long term workable solution.

The current thinking has been to equip the equip key staff with used EF Johnson 5100 series 700/800 Mhz radios that *I’m told* are fully compatible with the county's 800 MHZ trunked system. Our County uses Motorola radios on a 100% Motorola "bakend/core" system that supports SMARTNET and P25 and apparently everything 800 Mhz option under the sun. For example, our Police department can call a specific radio using a phone number and password, if needed (handy for areas with out good cell coverage). I am assured by the donor/EFJ Dealer that the EF Johnson will work with the county system, a walk around test approved by the county proved this out. Our County public safety tech person that admins the 800 MHZ Network is okay with the EFJ units on the Motorola network, but has told us “you are responsible for the handhelds, county is responsible for the airwaves”. The best analogy I have been given: ISP that offers bandwidth, I am responsible for the computers that plug into the connection. This make sense?

I’m worried about long term compatibility. Since they are used, the radios are being offered to us at a significant price break. Without getting into details, an organization/task force overbought the EFJ units a few years back, task force was disbanded – EFJ Dealer bought radios back from taskforce. Prices per radio are much cheaper that what I saw on eBay. The EFJ dealer is only charging us the “bench time” (I believe that is the right term??) to wipe the old radio configs and then put in the new county configs.

A few questions:
1. What are the differences between these the various EFJohnson models, please.
EF JOHNSON ASCEND ES 51
EF Johnson 51SL ES
EF Johnson 5100
Which is newer?? Would love to know the history of these models and how they compare technically. These are all 700/800 MHZ. I did a walk test with a EF Johnson 51SL ES. I'm told that the radios are built like tanks and can last a very long time, with the batteries being the bigger issue and the LCD screens might die after a period of many years. Correct??

If anyone has some links that shows the difference between the various EF Johnson 5100 versions, that would be very much appreciated. As the EFJ units are end of service or no longer made, I am hesitant to recommend a bunch (about 20) used radios. We have had technology donations in the past that have turned out to be pain filled long term maintenance projects for yours truly. I'm not getting a ton of rhythm that the local radio dealer offering the EF Johnson units is going to be there to support us long term. The EF Johnson Dealer has been wonderful to work with . Rumor is he is looking to retire soon.

2. Forgive my ignorance, but is it common to have RF transmission gear (Motorola in this case) from one manufacturer and radio handhelds from another? I was given a demo of the radio programmed on the county system, seemed to work “ok”. County has a digital trunked 800MHZ system that is “multi protocol”. While it is a rather advanced system, the county is a 100% Motorola shop. Apparently, some state politics got into play when the system was purchased. Motorola has a lot of pull on the state level.

Motorola dealer is only interested is selling us new Motorola equipment --- which we can’t afford. The original sales pitch seemed based on fear and a "generous" take it or leave it option. The local Motorola dealer services the countywide system. Motorola dealer is not the easiest people to work with. When talking with them, I get the feeling that Motorola has conveyed to their dealer network some type of papal license descended from Marconi himself. Motorola dealer for the county has been adamant that the only “workable” long term solution for the school is buy new Motorola radios from his company. Motorola dealer made a much different impression than the EF Johnson donor/dealer. EFJ dealer seems willing to go the extra mile. EFJ dealer is telling me that Motorola pulls the compatibility BS nationwide all the time. Thoughts?

3. Since we are a licensed school, the county is able to "rent" us a talk group for the radios. There is some talk of putting a booster repeater at the school to help increase coverage. County radio admin person likes this idea as the device would enhance coverage for our radios and the other county users (Police, Fire, Public Works). This county wide coverage would be ideal for field trips etc. The "walk test" I did with the EF Johnson's 5100 (700/800 MHZ radios) worked well outside. There were some dead spots in our brick building (older construction from 1970s --- been rehabbed and updated) that gave me concern. County has a spare repeater unit they said they could deploy at our school. In an odd twist, the school owns the land where a cell tower is currently located. I believe this would give us rights to place "something" on the tower at a steep discount, which would be w win for the county. School is in an expanding area of the county and the cell tower is apparently in a sweet spot for the wireless companies.

4. Security -- I'm told that Digital 800 MHZ trunked is “generally secure and mostly scanner proof” from people listening in?? As in you have to know what to program and all the codes to listen into the system?? If Child XYZ has an ADHD episode, we need to be mindful of that child’s privacy. Apparently, there are options on the EFJohnson to encrypt the voice channels. I would love to know if the encryption options (that are available on the radios being offered to us) would be long term workable with the Motorola trunking system?

If we activate AES on these radios does the Motorola repeater system have to be aware of the AES configurations? Can we use standard Motorola “signaling” on the radio but encrypt the voice audio? EFJ Dealer tells me my encryption request would make maintenance a pain in the a**? Would love someone else’s opinion on this issue. Have been told that AES can kill the coverage???

5. Features and reliability -- Our teachers are wonderful people, but in an urgent situation, we don’t need to be messing with tons of buttons. The EF Johnson programmable buttons (the red one on the top) seems wonderful as it could summon help rather quickly. EFJ dealer says it is rather easy to wire panic buttons into a desk unit if we need it, which would be a wonderful thing. County has offered to grant one radio (in the office) access to the county wide dispatch – also a big plus for us.

I'll try to keep this reply short and to the point. Feel free to ask follow up questions.

A few questions:
1. What are the differences between these the various EFJohnson models, please.
EF JOHNSON ASCEND ES 51
EF Johnson 51SL ES
EF Johnson 5100

As far as the 5100s go the model number doesn’t really matter as far as the hardware goes. They are all the same hardware within a series. What really matters is the version between the 5100s. A series 1 5100 (meaning it has 1.xx.xx firmware) is nowhere near as good as a series 6 (firmware 6.xx.xx)
The Ascend model just includes MultiNet trunking( EFJ version of SmartNet/Smartzone)
ES radios typically have less features enabled
Straight 5100s typically have more options enabled
The truth is all of these are the same radio though (within the same series)

All things being equal, take the higher series every time. It will have better hardware and better firmware.

2. Forgive my ignorance, but is it common to have RF transmission gear (Motorola in this case) from one manufacturer and radio handhelds from another
extremely common.

4. Security -- I'm told that Digital 800 MHZ trunked is “generally secure and mostly scanner proof” from people listening in?? As in you have to know what to program and all the codes to listen into the system?? If Child XYZ has an ADHD episode, we need to be mindful of that child’s privacy. Apparently, there are options on the EFJohnson to encrypt the voice channels. I would love to know if the encryption options (that are available on the radios being offered to us) would be long term workable with the Motorola trunking system?

As far as scanning, there are plenty of digital trunked scanners on the market never assume any open transmission is not being heard. The only way to keep comms truly secure is to utilize some form of encryption. The available encryption option on the EFJs depends on the model but for the most part they all include single key DES (or DES-OFB), unless it is a really old model. The trick here is getting a key put into the radio. Keyloaders are very expensive. If your dealer has an EFJ keyloader or a MOT KVL they could load them for you for a fee I would assume.
As far as the encryption type (AES vs DES) in a digital system it really doesn’t matter as digital just passes the encrypted audio stream. If this were analog then it would matter as that voice channel itself would have to be encrypted as well.
The buttons can be programmed for just about anything you may need. As far as reliability, I would not go with anything older than a Version 6 radio. These are MUCH more reliable than the predecessors.

Sean Penn: Last year I went to Iraq. Before Team America showed up, it was a happy place. They had flowery meadows and rainbow skies, and rivers made of chocolate, where the children danced and laughed and played with gumdrop smiles.